SURFICIAL GEOLOGY MAPPING OF NORTH CASCADES NATIONAL PARK

Surficial geology and soils have not been mapped in the remote, rugged National Parks of the Pacific Northwest. To provide data for future soils mapping, recognize disturbance patterns, identify key habitat, select long-term ecological reference sites, and to support other resource management programs, North Cascades National Park Service staff began mapping surficial geology in 1995. We are currently mapping the landscape at three scales, including Subsection (1:250,000), Landtype Association (1:62,500) and Landform (1:24,000) at North Cascades, Mount Rainier, and Olympic National Parks. Our mapping scheme is a hierarchical system that is integrated with the USFS ecological land classification system, providing seamless mapping across political boundaries and supporting ecosystem management principles. Landforms are the smallest functional units of the landscape, are easy recognizable, and are created by discreet geologic processes, many of which are active today in mountain areas. Mapping at 1:24,000 scale is the focus of our work, and is based on identification of 26 distinct landforms, including floodplains, alluvial fans, debris cones, landslides, terraces, floodplains, and moraines. Seven years of mapping in several North Cascades watersheds has provided important insight into the structure and function of the park ecosystem. For example, approximately 75% of the watersheds mapped are steep valley wall and barren, high elevation cirques. Further, only 2-3% of these watersheds are floodplain, which has important implications for survival of threatened and endangered aquatic species such as Chinook salmon and bull trout.